Silent Players of Health in a Broader Age-management Medicine Understanding: A Dissertation on Bacteriocin of Lactic Acid Bacteria

The preservation of foods in healthy and safe condition has long been used and still it remains an on-going challenge for food microbiologists. Drying, salting and fermentations were the traditional methods of preservation. Canning and freezing were relatively recent developments.The role of fermented milk in human diet in well known since Vedic times but the scientific interest arose only after the publication of a book “Prolongation of Life”(Metchnikoff, 1908). In developed societies, food preservation is viewed as a ‘convenience’ of an efficient food system, and food preservation is the key to ensure the availability of food as vital benefit. Food fermentations, developed by default rather than by design. Lactic acid bacteria (LAB) play an important role in food fermentations, causing the characteristic flavor, changes and exercising a preservation effect on the fermented product (Caplice and Fitzgerald, 1999). It is estimated that 25% of the European diet and 60% of the diet in many developing countries consists of fermented foods (Holzapfel et al.,1995). The spice trade was the start of addition of the chemicals adjunct to foods. With the industrial revolution and subsequent development of food industries, food processing moved from kitchen or cottage industries to largescale technological operations with increased need for food preservation. This stimulated the use of food additives, especially those that preserve the foods and enhance food quality. This has resulted in the emergence of a new generation of chill stored, minimally processed foods (de Souza et al., 2005).Hurst, (1973) reviewed the preservation of foods by the antagonistic growth of microorganisms. He showed the growth of lactic acid bacteria (LAB) in milk, saurkaut and vacuum packaged meats as examples of protective and antagonistic growth. In recent times this has been termed as ‘biopreservation’ to differentiate it from the chemical (artificial) preservation of foods.Biopreservatives such as lactic acid bacteria (LAB) and their metabolites have been investigated by several authors (Buncic et al., 1997; Pirttijarvi et al., 2001; Sakhare and Narasimha Rao, 2003). Considerable research has been done on the ability of LAB to inhibit growth of pathogenic microorganisms (Winkowski et al.,1993; MinorPerez et al.,2004). The capability of these bacteria to control growth of spoilage microorganisms has not been investigated to the same extent. To be successful in biopreservation, a bacteriocinogenic LAB culture must compete with the relatively high indigenous microbial load of raw meat, to actively inhibit pathogenic and spoilage bacteria (Sakhare and Narasimha Rao, 2003; Minor-Perez et al.,2004). Bacteria preserve foods as a result of competitive growth, products of their metabolism and bacteriocin production. Biopreservation refers to extended storage life and enhanced safety of foods using their natural or controlled microflora and (or) their antibacterial products. It may consist of (i) adding bacterial strains that grow rapidly and (or) produce their antibacterial products; (ii) adding purified antagonistic substance(s); (iii) adding the fermentation liquor or concentrate from an antagonist microorganism; or (iv) adding mesophilic LAB and other related bacteria as a ‘fail-safe’ protection against temperature abuse. LAB and other related bacteria produce lactic acid or lactic and acetic acid, and they may produce other inhibitory substances such as diacetyl, hydrogen peroxide, reuterin (α-hydroxypropionaldehyde) and bacteriocins (de Vuyst and Degeest, 1999).